The present invention relates generally to unitized seals, and more particularly, to a seal having plural pyramid shaped formations designed to reduce the temperature at the bumper wall-sleeve interface and also to provide additional beneficial effects. The seal design provides a slinging effect to grease on the inner side of the seal and provides a slinging effect on the external contaminants on the outer side. Moreover, the seal design provides a cooling effect to the interface between the bumper wall and the radial flange of the wear sleeve by utilizing the remains of the pyramid wall to create additional air convection.
The present invention provides a sacrificial member in the bumper wall that will abrade quickly under dynamic conditions, and thus relieve the compressive forces acting on the bumper wall. The net effect after a short break-in period is a line-to-line condition, between the sleeve and the remaining bumper wall, creating a barrier to environmental contacts. The present invention provides a tiny area, which gradually becomes bigger, and eventually is abraded into a parallel condition with the bumper wall on the radial flange of a unitized seal. This allows the pyramid shaped formation to wear away with a different degree of abrasion until, when it is completely or almost completely worn away, there is substantially line-to-line contact, or an area of minimal contact, between the bumper wall which was formed on the radial flange of the seal member and the wear sleeve. Accordingly, the seal can be assembled and placed in use with a maximum of confidence that the pyramid formations will wear away with a small amount of scrap rubber being thus generated.
The present invention relates mostly to large, heavy duty unitized seals wherein the wear sleeve is normally held against rotation and fixed over an axle stub or the like by means of a rubber inside diameter (I.D.) creating an interference fit. Of course, it could have other applications. In one embodiment, the seal is unitized by turning up an end portion of its axial flange, and the other or radial flange is acted upon by the pyramid shaped formation. The radial flange of the wear sleeve may also engage one or more dirt or dust lips or the like to prevent undue contamination of the seal area.
The seal itself, wherein the seal is bonded to a radial flange, includes the customary air side and oil side surfaces which meet along a seal band or line of intended contact with the wear sleeve. The seal body conventionally includes a groove for a garter spring and an accompanying garter spring to maintain the radial load on the seal. The axial end portion of the seal casing is also fitted with a rubber sleeve to allow for the seal to be installed with a rubber O.D. (outside diameter). The place where the seal casing axial flange turns into the radial flange contains a plurality of spaced apart chaplets, which are circumferentially discontinuous, and which present a radial face which is spaced just apart from the radial flange of the seal casing. These are termed “chaplets” or the like, and they terminate at a bumper wall which extends circumferentially around the seal casing. There are a plurality of small, spaced apart pyramid shaped formations which present four sidewalls, two of which have an identical shape and terminate on the casing, and the other two of which terminate on the end faces of the chaplets.
Accordingly, it is an object of the present invention to provide an oil seal of the unitized type or other seal having a bumper wall extending circumferentially around its radial flange with a plurality of pyramid shaped formations spaced circumferentially apart on the bumper wall.
Another object of the invention is to provide a unitized or other style of seal having a casing with a plurality of chaplets on its outside diameter, with the plural pyramid shaped formations intersecting the chaplets.
Another object is to provide a plurality of pyramid shaped formations which are circumferentially spaced apart and in which the pyramid forms an initial contact with the sleeve, and wear an ultimately near zero clearance with a radial flange of the wear sleeve.
Another object of the invention is to provide a pyramid shaped formation riding on a bumper wall, with an excluder or secondary seal being provided to increase the security of the slidable connection between the flange of the wear sleeve and the casing of the seal unit.